AOAC Official Method 934.03 Soybean Flour in Uncooked Cereal Products
Qualitative Test
First Action 1934
Final Action 1976
Place ca 0.5 g test portion in small test tube containing strip of red litmus paper partly immersed in 5 mL 2% urea solution (w/v). Mix, stopper tube, and heat 3 h at 40°C. If soybean flour is present in more than traces, litmus paper turns blue. (Bromothymol blue may also be
used as indicator; it likewise turns blue if soybean flour is present.)
Reference: JAOAC 17, 329(1934).
